This invention relates to a control mechanism for a chair or the like, and particularly to a tilt and height control mechanism for a chair.
Tilt controls for chairs are known. Most are cumbersome and complicated, and oftentimes not reliable. The present invention has, for its principal object, the providing of a control mechanism for a chair in which tilting action may be easily and effectively controlled, as well as chair height adjustment.
In a preferred embodiment of the present invention, tilt and height control are achieved through use of a single self-contained adjustment mechanism controlled by a single adjustment lever. In one position of the lever, the chair is "locked" so that it may not be tilted. In another position of the lever, the mechanism is "unlocked" and the chair may be tilted to any comfortable position. In still another position of the lever, the chair height may be adjusted, as desired.
This action is achieved in a preferred embodiment of the invention by use of a control housing that is attached to a chair seat and a pivot block that is attached to a chair pedestal or similar chair support mechanism. The control housing and pivot block are mounted for pivotal movement with respect to each other about a pivot shaft. An actuator block is supported for movement along that shaft and carries a pin thereon. The control housing includes a flange which engages the pin in one of the positions of the actuator block along the shaft, thereby preventing pivotal movement of the control housing and pivot block. In another position of the actuator block along the shaft, the pin and flange are out of disengagement (the flange is discontinuous), so that pivotal movement of the control housing and pivot block can take place. In this fashion the chair is either locked against tilting or unlocked for tilting. In another position of the actuator block along the shaft, a cam surface on the actuator block engages the actuator control of a gas cylinder mechanism, permitting the height of the chair to be adjusted. The position of the actuator block along the pivot shaft may be controlled by a spring-loaded ball carried by the actuator block which engages grooves in the pivot block corresponding to the tilt locking and tilt unlocking positions of the actuator block. The actuator block preferably is spring-biased out of the position thereof along the shaft in which the actuator control of the gas cylinder mechanism is activated.
The assembly preferably includes a wear strip that is mounted to the pivot shaft, is formed of spring metal, and has a surface that is positioned adjacent to the cam surface of the actuator block. The actuator block is moveable along the pivot shaft with respect to the wear strip, and the wear strip is adapted to engage the actuator control of the gas cylinder mechanism.
The control housing and pivot block pivot with respect to each other, as noted above, about the pivot shaft. A coil spring is utilized urging the control housing and pivot block toward a predetermined angular relationship with respect to each other about that shaft. The coil spring provides the conventional restoring force against the tilting of the chair tending to return the chair to a non-tilted position.
The invention will be more completely understood by reference to the following detailed description.